Spray gun



Oct. 3, 1933.

R. M. CATHCART 1,929,348

SPRAY GUN Filed Jan. 30, 1951 2 Sheets-Sheet l zeofierz MT Caz fipari.

Oct. 3, 1933. R. M. CATHCART SPRAY GUN 2 Sheets-Sheet 2 Filed Jan. 30, 1931 5 M r g m M W) hw g y 7, z M A 11% z I E a Patented Oct. 3, 1933 1 ei er 30, 1931,. Serial No. 512, 21 1" 3 Claims. (01. 91-455 This invention relatest'o spray apparatus and has for anobjectto provide novel means whereby nozzle jamming .material. will be forcibly ejected from the barrel of a spray gun intothe atmosphere when the compressed air is directed in a retrograde direction through the nozzle to dislodge the jamming material.

A further object is to provide a blow-off or waste fitting, disposed in the material feed line to the gunancl valve controlled to permit'of the gun being instantly freed of nozzle jamming material, without disconnecting any of the parts- 'of the apparatus. 1 v V A still further objectis to provide a three-way valve, manipulation of which'wilLin' addition to the'foregoing, also permit of flushing the feed line with an acceleratedfiow' ofiresh material for relieving said line of :any accumulation of clogging masses or foreignv substances.

A still further object of the invention is to provide an apparatus wherein, aftera scavenging fiuid has been introduced into the tank, the valve may be, without the necessity of disconnecting any of the parts, opened for permitting an accelerated'ilow of the fluid through the feed-line to the atmosphere so that said fluid will be forcibly driven through the line for. dislodging any.in--

crustations and quickly and effectively cleaning theline.

With the above and other objects in view the invention consists in certain novel details of construction and combinations of parts hereinafter fully described and. claimed, it being understood that various modifications may be resorted to within the. scope of the appended claims without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawings of this specification:

Figure 1 is a perspective view, with parts in elevation, showing the air compression tank and spray gun of conventional construction, the spray gun being equipped with myimproved purging valve. Fig. 2 .is a detail sectional'view showing .the purging valve in one operative position, V

Fig. 3 is a detail sectional view showing.- the valve in position to afford direct communication between the material hose and the materialbarrel ofthe spray gun, and

Fig. 4 is a view similar to Fig. 3 but showing the valve turned to establish communication between the material hose. and waste pipe.

forming part A jamin the spray gun, while spraying texture, causesrimperfect finish on'the walls or ceiling while working the trigger to dislodge the jamming material, the stipple varying from coarse chunks down to a fine atomized spray. Even if this blotching of walls and ceiling did not occur, still a very serious loss in a workmans time and terial barrel :of'the gun in in material is caused during the courseof'a days work, especially in the sprayingof viscuous fiuids, such as asphalts, cementaplasters, aggresgates, etc., by the very frequent jamming of the spray gun. Usuallyfthe ,work'man' places his handover the nozzle of thegun to" cause-the compressed air'to back up ormove in a retrograde direction through the nozzle, and simultaneously works the trigger. to dislodge the chunks whic'h may be blocking the needle valvecontrol'or even the entrance of the fluid'supply hose to the meterial barrel of the gun. This procedure results in the chunks being blown back into the; material pipe only to again jam the gun, usually 'within a few minutes moreor less. 7 l The only practice certain to work islab'orious and time consuming andusually consists in firs't cutting off the pressure from the compressor 10 in the: air line 11 by closing the inletair valve 12. Next, the operator lets the pressure out of the tank 13 to prevent boiling, byunscrewing the escape valve 14.- Next, the material hose 15 is disconnected from the spraygun; Then the air hose 16 is disconnected from the airoutlet'valve 17. The cleaning of the gun now takes place by putting the nozzle of the gun-tight-up against the open air valve 17 ands'uddenly opening the air valve 12jwhile at the same timepulling the trigger toopen the fluid barrel, -thus le'tting a pressure of from '75 to 100 pounds of air pass through the gun andblowing out'the' obstructing material. After purging, th'e various valves and connections must be returned to the adjustment necessary for spraying. All this 'takes'timejis messy, and oftentimesmesults in an appreciable waste of material. 1 To obviate the above cleaning present invention contemplates the use or prefer ably 'a three-way valve connected with the mathe rear of'thenozzle and, when opened, the operator meanwhile holding his hand over the-nozzle and pulling in a' retrograde direction-through the nozzle 'to dislodge'the jamming" material'and blow the same into the atmosphere without loss of time by equipment adjustment or defacement of the walls and ceiling being treated.

ordinarily constitutesmeans for connecting the end of the material hose 15 to thegun but, in the present embodiment of the invention, is utilized for attaching the flanged outlet nipple -22 eta valve casing 23 to the pipe. The inlet 'nipple'24 of the valve casing is connected by a gland nut 25, shown in Fig. 1, to the material hose 15. The

the trigger, permitting the compressed air to -pass procedure, the

the rear'of the nozzle--20 of the gun.

Preferably, a three-way rotary valve 28 is mounted in the valve casing and is controlled by a lever handle 29. As usual in this type of valve,

there is a run port 30 and a lateral port 31.

When the valve handle 29 is turned forwardly, as shownin Fig. 2, the lateral port 3l and run port 30 establish communication between the material barrel 18 of the gun and the waste pipe 27. In this position of the parts, blocking material, such as lumps 32 may be dislodged and blown ontof thejgunyby pressing the trigger 33 to withdraw the needle valve 34, and simultaneously placing the hand, as shown at .35, over the nozzle, it being understood, of course, that the trigger controls both the material :and compressed air supply. The compressed air, entering the nozzle from the compressed air barrel 37 of the gun, is thus direct-ed back in -a retrograde direction through the nozzle, as shown by the'arrow-heads. In practice it is found that the blocking material is dislodged instantlyand with a sharp report similar .to an air-rifle and forcibly ejectedfrom zthewspray gunthroug-h the waste pipe 27 into the atmosphere. 1

The valve handle 29 ordinarily is turned upwardly, as shown;best by dotted lines in Fig. 3, to dispose the run port 30 of the valve to establish communication betweenthe material intake pipe 19 of the gun and the material supply hose 15. In this position of the parts, the material is fed from the hose :to the spray gun without obstruction;

,As shown best in Fig.4, the .handle 29.may be turned horizontally 'rearwardly to dispose the run port 30 of the valve and the lateral port 31 to connect the material hose 15 with the waste pipe 27. As the ports 30 and 31 of the valve are of substantially the same diameter as that of the hose 15, the passage of material through the hose and ports will be unimpeded so that in this position of "the parts, the operator is enabled to flush the hose by an accelerated flow of fresh material from the tank as well as test the consistency of the material by permitting a quantity to escape from time to time, as desired. Furthennore, after the material has been removed from the tank at the completion of work, kerosene may be introduced into the tank, p ly when by turning on the air the kerosene may be .forcibly driven through the hose for tearing loose any lumps of material therein and dislodging'any incrustations to thus quickly and efiectually clean the feed line.

From the above description-it will be observed that the operator is permitted, byuse of the novel valve fitting above described, to maintain absolute control over his material at alltimes. In the morning, when the operatoris starting up, it enables him to blow off the first fluid into the waste bucket. taking'all the scale and dirt from the without disturbing a single connection. Furthermore, in all cleaning of equipment, it enables the operator to blow the cleaning fluid through the equipment in minimum time without disturbing a single connection. Furthermore, it permits of instantaneous dislodgmentof particles, such aschunks or :the like, which may jam the gun, without loss of time and without defacing the walls, ceiling or-anysurface being treated.

'Having thus describedthe invention, I claim:

1. As a purging means for spray apparatus wherein material is fed to a gun from a tank by air pressure in the tank, the combination of a gun having air and liquid passages associated whereby air from the air passage may be directed backward into the liquid passage, a supply tank adapted to contain material as well as air under pressure tending to expel the material from the tank, means for feeding compressed air to said air passage, a feed line for conducting material from the tank to said liquid passage, and means for closing the feed line to maintain constant the air pressure in the tank and venting said liquid passage to the atmosphere whereby, by manually diverting a portion of the air issuing .fromv the air passage into and back through the'liquid passage and through said venting means, said liquid passagemay be purged of 'cloggingmaterial without disturbing the adjustments of the tank or returning said clogging material to the tank.

2. As a purging means for spray apparatus wherein material is fed to a gun from a tank by air pressure in the tank, the combination of a gun having air and liquid passages associated wherebyair from the air passagemay be directed backward into theliquid passage, a supply tank adapted to contain material as 'well as :air under pressure tending to expelthe material from the tank, means for 'feeding compressed air to said .air passage, a feed line for conducting material from the tank to said liquid passage, and a twoway valve in the feed line movable to one position for closing the feed line to maintain constant the air pressure in the tank and venting said liquid passage to the atmosphere whereby, y manually diverting a portion of the .air issuing from the air passage into and back through the liquid passage and through said valve, said liquid passage may be purged of clogging material without disturbing the adjustments of the tank or returning said clogging material to the tank, and movable to another position tovent to the atmosphere that portion of the feed line extending from the valve to the tank for purging the feed line without disturbing the adjustments of the tank. I

'3. In spray apparatusthe combination with a compression ,tank, of a spray gun including a liquid nozzle, an air liquid nozzle whereby air from the air nozzlemay be directed backward through the-liquid nozzle, a needle valve for controlling the admission of liquid to the liquid nozzle, means for feeding compressed air to the air nozzle, a feed line to supply material from the tank to the liquid nozzle, and valvular means in the feed lineadapted to close the feed line to maintain compression in the compression tank and prevent backward flow of the material from the liquid nozzle through the feed line into the compression tank and adapted also to vent to theatmosphere the feed line between the valvular means and the liquid nozzle whereby; by diverting a portion of the air issuing from the air passage into and back through the liquid passage and through said valvular means, said liquid passage and said needle valve may be purged of clogging material without disturbing the adjustments of the compression tank or returning said clogging material to the tank.

ROBERT M. CATHCART. [15.8.]

nozzle associated with the v 

